| With the rapid development of urbanization and the continuous growth of urban population,people have higher requirements for the beauty of the architectural space,and the special-shaped column frame structure is more and more used in the urban residential buildings.Ordinary special-shaped columns exist the main problems is low bearing capacity and difference ductility,therefore,this paper put forword using high strength stirrups restraint and micro steel-fiber cement composite materials special-shaped column,observated the failure form of special-shaped column,analysised the influence of the stirrup spacing,concrete strength and steel fiber content on bearing capacity and ductility of the specimens,pushing the bearing capacity formula of peak strength of concrete columns with cruciform constraint increases the value calculation formula and test pieces.This paper designed a total of 24 specimens,the number of cross section and T-shaped specimens all is 12,the stirrup spacing is divided into 40mm,70mm,100mm,strength grade of concrete matrix was designed two gradient,In the cross section and T-shaped columns,there is a group of cement-based composite specimens as the control group,the remaining three groups are superfine steel fiber cement matrix composite specimens.axial compression tests of 24 special-shaped columns are carried out.Axial compression tests of special-shaped column with ultra-fine steel fiber based cement composites,The results showed that the stirrup spacing,ultra-fine steel fiber content,concrete strength grade have different degree of influence to the load-carrying capacity and ductility of specimens,The fitting formula for increasing the peak strength of cruciform section confined concrete is established,and the bearing capacity calculation formula of the cruciform specimen is derived.The calculated value of the bearing capacity is in good agreement with the experimental value,and it can accurately predict the bearing capacity of the specimen. |
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